This invention relates to alarms for milk coolers and more particularly to an alarm which sounds when the temperature of milk within a milk cooler exceeds a predetermined value.
According to conventional practice on a dairy farm, milk is drawn from cows by means of a milking machine and flows through a series of conduits to a cooler where its temperature is reduced to about 4 degrees C. An agitator within the cooler ensures that the temperature is uniform throughout the volume of milk.
The cooler maintains the milk at the required temperature until the milk is discharged onto a tanker truck for transportation to a dairy. Once the milk has been discharged, the cooler is scoured with hot cleaning solvent to make it suitable for the next load of fresh milk.
The milk may remain in the cooler for a matter of hours or days depending on the frequency of pick up by the tanker truck. During this time, the milk must be maintained at the required temperature to preserve its quality. Should the cooler malfunction or cease operating because of an interruption of power, the milk may spoil.
Since a milk cooler may contain one or more days' production of milk on a dairy farm, the spoilage of its contents represents a significant economic loss to the farm. In order to minimize the possibility of spoilage for this reason, warning devices of various constructions have been devised for use in conjunction with milk coolers. Typical of such devices is one which consists of a warning lamp which is illuminated when the cooler is operating normally but which goes out when the cooler ceases functioning.
Such a warning device has many shortcomings the most serious of which being that it requires continuous monitoring to be effective. If a farmer is unable to inspect the warning lamp at frequent intervals it will be of only marginal usefulness to him since it will not tell him that the cooler has stopped working if the cooler stops at a time when he is unable to inspect the lamp.
Another shortcoming of such a warning lamp is that it does not indicate whether the cooler is operating when it contains milk. The cooler may be consuming electricity but not be functioning properly yet the warning lamp will be illuminated and be indicating that nothing is amiss.
A still further shortcoming of the warning lamp is that it fails to warn the farmer that the cooler is not turned on when it should be. For example the farmer may have shut off the cooler to permit him to empty it or clean it with cleaning solvent. The warning lamp lacks means, independent of the farmer, for ensuring positively that the cooler is turned back on after it has been emptied or cleaned. Should therefore, the farmer forget to turn the cooler back on when fresh milk is being introduced into the cooler he will not be warned that the cooler is not operating.